How can I enable the Laplacian Lightning Generator?
Read about the API change:
http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.66/Addons#Restricted_Context

And here I posted an example script to show a possible solution:
http://wiki.blender.org/index.php/Extensions:2.6/Py/API_Changes#Restricted_Context

There's also a hack to circumvent the context restriction:
Add an app handler for the scene_update_post event, let it remove itself and run the initialization code in the body.